Intro to Physics

Newton’s Laws of Motion (Chapters 3; 6.1-6.6; 7.1-7.4)

Inertia and mass / Friction
Newton’s 1st Law of Motion (law of inertia) / Pressure
Newton’s 2nd Law of Motion
(Fnet = ma) / Forces occur in pairs (force pairs)
Newton’s 3rd Law of Motion
(Action Force = Reaction Force) / Graphical relationships with mass, force, acceleration, and velocity
Inverse and direct relationships
Aristotle, Galileo and Newton

Essential Question: How are Newton’s Laws of motion used to describe the motion of an object and changes that occur?

Student Objectives

  1. State Newton’s three laws of motion.
  2. Explain how Aristotle and Galileo/Newton differed in their explanations of why objects stay moving and why objects stop moving.
  3. Interpret how inertia helps to explain the motion of objects.
  4. Explain the relationship between mass and inertia.
  5. Explain what causes an object to change its motion.
  6. Explain the difference between a directly proportional and inversely proportional relationship.
  7. Solve motion problems using Newton's second law of motion.
  8. Explain the relationship between net force and acceleration if mass is kept constant.
  9. Explain the relationship between mass and acceleration if the net force is kept constant.
  10. Use a = F/m to explain why two objects in freefall having different weights fall with the same rate of acceleration.
  11. Explain what causes an object to accelerate.
  12. Identify action-reaction force pairs
  13. Using the first, second and third laws of motion, explain the motion of objects in different situations.
  14. Explain friction’s role in changing motion.
  15. Explain the difference between pressure and force.

Intro to Physics

Momentum, Impulse and Law of Conservation of Momentum Unit Guide

Chapter 8.1, 8.2, 8.4 and 8.5

Key Terms

Momentum / Impulse-Momentum Theorem
Impulse / I = Ft
Law of Conservation of momentum / p = mv
Perfectly inelastic collision / Ft = Δmv
Perfectly elastic collision

Essential Question

  • How is momentum conserved in collisions?

Unit Objectives

  1. Define momentum and impulse and show representative equations and units.
  2. Explain how the momentum of an object can be increased or decreased.
  3. Explain how objects with greatly different masses can have the same momentum.
  4. Solve momentum problems and impulse problems.
  5. Explain how impulse is influenced by changes in the acting force and the length of time the force acts.
  6. Explain why impulse is so important to safety.
  7. Explain the law of conservation of momentum using the examples of a game of pool and of a cannon firing a cannonball.
  8. Explain the difference between elastic and inelastic collisions.
  9. Explain how momentum is conserved in elastic and inelastic collisions.
  1. ens during a car accident where the car collides with a tree at 20 mph.
  2. If a golf club strikes a golf ball, which receives the greater force, the ball, the club or do they both receive the same force?

3.Does a falling apple pull up on the Earth as it is falling? Explain.

4.Does the Earth pull on the Moon with the same force that the Moon pulls on the Earth?

5.With what force does the pavement push on a car weighing 4000 N?

6.If you are in an elevator that pushes you upwards with a force that doubles your weight, how does this change acceleration?

7.If a little girl is pulling with 500 N of force on a rope in a tug of war against her bigger sister, does the bigger sister pull with greater force? Explain.

9.Use the third law to explain how a rocket moves through space.

10.Use the third law to explain why a car moves down the road.

11.Use the second and third law to explain what will happen when a train hits a truck that stalled and was quickly abandoned on the rail crossing.

12.Use the second and third law to explain the forces acting on a cannon and cannonball when fired, and why each has a different acceleration.

13.Do forces always act in pairs? Are they always equal and opposite?

14.Using the first, second and third laws of motion, explain why the Earth orbits the Sun.

15.Using the first, second and third laws of motion, explain what happens during a car accident where the car collides with a tree at 20 mph. Consider the car is carrying a driver and a passenger.

Intro to Physics Unit Guide

Newton's First, Second and Third Law of Motion

Chapter 3.4, 6.1-6.3; and 7.1-7.4, 7.7

Key Terms

Inertia / Inverse relationship / Newton’s First Law
Mass / Direct relationship / Newton’s Second Law
Law of Inertia / Fnet = ma or F = ma / Newtons’s Third Law
Newton / Action force
Kilograms / Reaction force

Newton’s 1st Law

1.State Newton’s First Law of Motion.

2.What are the relationships between mass, inertia, and accelerating force?

Newton's 2nd Law

1.Explain the difference between a directly proportional and inversely proportional relationship.

2.How can you recognize an inversely and directly proportional relationship on a graph?

3.State Newton's Second Law of Motion.

4.Solve motion problems using Newton's second law of motion.

5.Explain the relationship between net force and acceleration if mass is kept constant.

6.Explain the relationship between mass and acceleration if the net force is kept constant.

7.Consider two objects, one with 1 kg of mass and the other with 10 kg of mass. Use a = F/m to explain why these two objects, neglecting air resistance, fall at the same rate of acceleration.

8.Explain what causes an object to accelerate.

9.Could you argue that acceleration and change of velocity mean the same thing? Explain.

10.Explain the relationship between mass and acceleration when an average-sized football player tries to block a person who is much heavier and a person who is much lighter.

Newton's 3rd Law

1.State Newton's third law of motion.

2.If a golf club strikes a golf ball, which receives the greater force, the ball, the club or do they both receive the same force?

3.Does a falling apple pull up on the Earth as it is falling? Explain.

4.Does the Earth pull on the Moon with the same force that the Moon pulls on the Earth?

5.With what force does the pavement push on a car weighing 4000 N?

6.If you are in an elevator that pushes you upwards with a force that doubles your weight, how does this change acceleration?

7.If a little girl is pulling with 500 N of force on a rope in a tug of war against her bigger sister, does the bigger sister pull with greater force? Explain.

9.Use the third law to explain how a rocket moves through space.

10.Use the third law to explain why a car moves down the road.

11.Use the second and third law to explain what will happen when a train hits a truck that stalled and was quickly abandoned on the rail crossing.

12.Use the second and third law to explain the forces acting on a cannon and cannonball when fired, and why each has a different acceleration.

13.Do forces always act in pairs? Are they always equal and opposite?

14.Using the first, second and third laws of motion, explain why the Earth orbits the Sun.

15.Using the first, second and third laws of motion, explain what happens during a car accident where the car collides with a tree at 20 mph. Consider the car is carrying a driver and a passenger.